Sur d’autres sites (11345)

• Unable to get the audio from webcam and play it at the same time [FFMPEG]

  5 avril 2019, par Apoorv Mishra

  I’m trying to grab the audio and video from the webcam and play it in slow motion and proper sync between audio and video at the same time. But when I try the following command :

  ffmpeg -f v4l2 -rtbufsize 1000000k -i /dev/video0 -f alsa -i default \
  
  -profile:v high -pix_fmt yuvj420p -level:v 4.1 -preset ultrafast \
  
  -tune zerolatency -vcodec libx264 -r 10 -b:v 512k -s 640x360 \
  
  -acodec aac -strict -2 -ac 1 -b:a 64k -b:v 300k -g 30 -ar 44100 \
  
  -map 0 -f tee "output.mkv|[f=nut]pipe:" | ffplay \
  
  pipe: -vf "setpts=2.0*N/FRAME_RATE/TB"

  I was unable to hear the audio. In the command, I’d only slowed down video but I will slow down the audio as well once I’ll be able to get the audio along with the video.

  Above command will play the video for you but not the audio.

  Please help me out with this. Any help is appreciated.

• Cannot play MPEG-TS from webcam using ExoPlayer on Android or Quicktime on Mac

  6 février 2017, par Galaxy

  I’m trying to use FFmpeg to stream my webcam to an Android device based on the HttpLiveStreaming(HLS). In order to play the MPEG-TS on Android, I use ExoPlayer.

  ---

  FFmpeg streaming command : ffmpeg -f avfoundation -video_size 1280x720 -framerate 30 -i "0" -vcodec libx264 -preset veryfast -f flv rtmp://localhost:1935/hls/test

  When I used VLC to play the MPEG-TS, everything was OK. However, I failed to play it using the ExoPlayer on Android or the Quicktime(Safari) on Mac OS. Then I tried to find out the reason.

  ---

  I tried to stream a mp4 video using FFmpeg in the same way. For example : ffmpeg -re -i test.mp4 -vcodec libx264 -preset veryfast -f flv rtmp://localhost:1935/hls/test

  I can play it using both ExoPlayer and Quicktime.

  ---

  The only difference I found between these two cases is that the Webcam’s capturing format is YUY2 while the mp4 video is YUV420 and they used different H264 encoders. I guess the H264 decoders for YUY2 and YUV420 are not the same.

  I’m not sure if my inference was correct and the only solution to this problem is to convert YUY2 to YUV420 before streaming.

  I hope someone using Mac could try to stream the Facetime camera using the same way as me and see if it can be played in the Safari.

• PS4 can not play h264 vedio

  21 octobre 2019, par Alex Chiang

  Summary

  PS4 Media player can not play h264 mkv, avi or mp4 movies which were converted from HEVC. According the sony’s [docs], the media player could be.

  source
  video : HEVC
  audio : AC-3

  converted
  video : H264
  audio : AC-3